Often called the "chicken of the woods," Laetiporus sulphureus used to be an easily recognized orange polypore with fairly soft flesh, widely distributed in North America. However, recent DNA and mating studies (see Burdsall & Banik, 2001) have complicated things, since diverse North American "Laetiporus sulphureus" specimens did not feel like throwing a Transcontinental Gene-Exchange Festival in the laboratory. The resulting six North American species (and one species variety) of Laetiporus also demonstrate clear ecological separation, occurring in different ecosystems and/or performing different ecological roles.

Laetiporus sulphureus, it turns out, is limited to eastern North American hardwood forests, where it causes a brown heart rot in the wood of standing and fallen oaks and other hardwoods. Since it is a heart rot fungus, the mushrooms appear above ground (often high on the tree)--or in a position that would have been above ground before the trunk fell. Laetiporus cincinnatus also appears in eastern hardwood forests, but is a root and butt rot fungus and therefore appears at the butt of the tree or on the ground near its base (additionally, Laetiporus cincinnatus has a whitish, rather than yellow, pore surface). See the notes below on three other North American species.

Description:

Ecology: Parasitic and saprobic on living and dead oaks (also sometimes on the wood of other hardwoods); causing a reddish brown cubical heart rot, with thin areas of white mycelium visible in the cracks of the wood; annual; growing alone or, more typically, in large clusters; summer and fall, rarely in winter and spring; east of the Rocky Mountains. The mushrooms do not appear until well after the fungus has attacked the tree; by the time the chickens appear, they are definitely coming home to roost, as far as the tree's health is concerned.

Fruiting Body: Up to 60 cm across; usually consisting of several to many individual caps arranged in a shelving formation or a rosette.

Caps: 5-30 cm across and up to 20 cm deep; up to 3 cm thick; fan-shaped to semicircular or irregular; more or less planoconvex; smooth to finely wrinkled; suedelike; bright yellow to bright orange when young, frequently fading in maturity and with direct sunlight.

Laetiporus gilbertsonii grows in coastal western North America, from Oregon to Baja California, and along the Gulf Coast (where it has a whitish pore surface), on oaks and eucalyptus. The type collection for the species was made in Golden Gate Park, on eucalyptus. It is morphologically indistinguishable from Laetiporus sulphureus, but the two species will not "mate" in culture, making them biologically distinct. It can be found growing on deadwood and on living trees. Laetiporus conifericola, illustrated to the right, grows on living and dead conifer wood in western North America. Though morphologically indistinguishable, it is easily separated from other species of Laetiporus by its range and host wood. It has (very) slightly larger spores (6-8 x 4-5 µ). It, too, is a biological species--but it will mate, about 15 percent of the time, with a conifer-loving chicken from the Great Lakes area, Laetiporus huroniensis (which is much more often than I would).